The development of rechargeable batteries as energy storage devices is a key issue for many future applications. Lithium is typically used in re-chargeable batteries, but its abundance and geographical distribution are a matter of debate. Due to lithium resources and cost, the use of sodium is attractive for use in rechargeable systems. A few cathode materials have been investigated for use in sodium batteries [see Lu, Z et al. Electrochemical Society, 148; A1225-A1229 (2001); and Cao, Y. L et al. Adv. Mater. 23; 3155-31581, (2011). However, the main obstacle facing such systems is the anode composition.
In addition, environmental effects and sustainability, demand that low-polluting, organic materials be considered for use, without the presence of heavy metals. For example X. Han et al. [see Adv. Mater. 19, 1616-1621 (2007)] shows that aromatic carbonyl derivative polymers such as 3,4,9,10-perylenetetracarboxylicacid-dianhydride (PTCDA) can insert lithium near 2.5V. This material has been proposed as cathode material for lithium batteries. Conjugated dicarboxylate based materials such as di-lithium trans-trans-muconate and di-lithium terephthalate (abbreviated thereafter as Li2BDC) were also studied as organic anode material for lithium batteries [see Armand et al. Nature Materials 8; 120-125 (2009)]. U.S. Patent Publ. No. 2010/0237298 proposes the use of quinone based materials for lithium battery applications. U.S. Patent Publ. No. 2003/0148188 describes the use of tetraketopiperazine based materials as positive cathodes for lithium batteries applications.
Flow batteries are rechargeable systems where at least one electrode (anode or/and cathode) is soluble in a solvent. For example, a soluble anode can insert any kind of cations. An example of this flow battery system is published by Li et al. (Electrochemial and Solid State Letters 14(12); A171-A173 (2011)). Li describes the use of 2,2,6,6-tetramethyl-1-piperidinyloxy and N-methylphthalimide as an all-organic redox flow battery. Unfortunately, the battery voltage is only 1.4V due principally to the high voltage insertion of the anode N-Methylphthalimide, which is close to 1.7V vs lithium.